Gwyneth Paltrow shares the secret to looking like an A-lister, and it's apparently all in the heavy eye makeup.

The 42-year-old "Iron Man" actress shared before and after Instagram selfies on Tuesday. The first was of her seemingly makeup-free, while the other showed Paltrow camera ready, wearing loads of mascara and eyeshadow. "Day-to-night," she wrote. "I nominate @amandadecadenet to share her most glamorous transformation. #GlamJan #sp @maxfactor."

Paltrow is baring her pores as the new face of Max Factor. This past year, she channeled Marilyn Monroe for the brand's "Femme Fatale 40's," and admitted she was pretty fond of the transformation. "It's fun to dress up for work," she said in a behind-the-scenes video of her Max Factor photo shoot. "You know, it's always nice to be in New York, in a little convertible Mercedes, and it's good."

While eye makeup seems to be the big ticket in the actress' recent Instagram selfie, that's not what she says is the most important item to have when getting dolled up. "I think I like the lipstick the best."